The present embodiments are directed to curable inks, such as e-beam curable inks and ultraviolet (UV) curable inks. Curable inks generally include at least one curable monomer, a colorant, and a radiation activated initiator that initiates polymerization of curable components of the ink. In particular, the curable ink is an UV curable gel ink. In particular, the curable ink is an UV curable ink including a gelator. These UV curable gel ink compositions can be used for ink jet printing in a variety of applications. The UV curable gel ink of the present embodiments comprises a diurethane gelator.
UV curable gel inks are known. They are for example disclosed in, for example, U.S. Pat. Nos. 7,153,349, 7,259,275, 7,270,408, 7,271,284, 7,276,614, 7,279,506, 7,279,587, 7,293,868, 7,317,122, 7,323,498, 7,384,463, 7,449,515, 7,459,014, 7,531,582, 7,538,145, 7,541,406, 7,553,011, 7,556,844, 7,559,639, 7,563,489, 7,578,587, 7,625,956, 7,632,546, 7,674,842, 7,681,966, 7,683,102, 7,690,782, 7,691,920, 7,699,922, 7,714,040, 7,754,779, 7,812,064, and 7,820,731, the disclosures of each of which are totally incorporated herein by reference. UV curable gel inks can exhibit desirable characteristics such as improved hardness and scratch-resistance and improved adhesion to various substrates. Curable gel inks can also exhibit advantages in that dot spread of the ink can be controlled, the ink does not bleed excessively into the substrate, including porous substrates.
A key component of the curable gel inks is a phase-change gelling agent (or gelator) enabling wide substrate latitude, excellent adhesion, and enhanced pigment dispersion stability. There remains a need to explore and identify new gelator molecules that are suitable for use as phase-change materials for curable inks, as thickeners for coating formations, or in other printing applications, such as 3D printing. The sharp increase in ink viscosity upon printing offers numerous advantages over non-phase change inks, namely: controlled spread (dot gain) and minimum bleed-through (jet-through) on porous substrates, wide substrate latitudes, minimal paper cockle and distortion, and the ability to rapidly build up raised print features for 3D printing without intermediate curing steps.